1. Technical Field
The present disclosure relates to a foreign object detecting device for detecting foreign objects, such as metal, human bodies, and animals, being present near a wireless power transmitting apparatus in a wireless power transfer system. The present disclosure also relates to a wireless power transmitting apparatus and a wireless power transfer system including such a foreign object detecting device.
2. Description of the Related Art
Nowadays, various mobile devices, for example, cell phones, are becoming widespread, and power consumption in mobile devices is increasing due to their enhanced functions and performance and an increase in the variety of the content. If power consumption in a mobile device operating with a limited capacity of batteries increases, the operating time of the mobile device decreases. As a technology for compensating for a limited capacity of batteries, a wireless power transfer system is attracting a lot of attention. A wireless power transfer system wirelessly transfers power from a wireless power transmitting apparatus (hereinafter simply referred to as a “power transmitting apparatus”) to a wireless power receiving apparatus (hereinafter simply referred to as a “power receiving apparatus”) by utilizing electromagnetic induction between a power transmitting coil of the power transmitting apparatus and a power receiving coil of the power receiving apparatus. Particularly in a wireless power transfer system using a resonance-type power transmitting coil and power receiving coil, high transmission efficiency can be maintained even when the position of the power transmitting coil and that of the power receiving coil are displaced from each other. Accordingly, the application of such a wireless power transfer system in various fields is being expected. It may be possible to widen the area where mobile devices can be charged by increasing the size of a power transmitting coil or by forming an array of multiple power transmitting coils.